Warm Jupiters not as lonely as expected

July 14, 2016, Dunlap Institute for Astronomy & Astrophysics
An artist's portrayal of a Warm Jupiter gas-giant planet (r.) in orbit around its parent star, along with smaller companion planets. Credit: Detlev Van Ravenswaay/Science Photo Library

After analyzing four years of Kepler space telescope observations, astronomers from the University of Toronto have given us our clearest understanding yet of a class of exoplanets called "Warm Jupiters", showing that many have unexpected planetary companions.

The team's analysis, published July 10th in the Astrophysical Journal, provides strong evidence of the existence of two distinct types of Warm Jupiters, each with their own formation and dynamical history.

The two types include those that have companions and thus, likely formed where we find them today; and those with no companions that likely migrated to their current positions.

According to lead-author Chelsea Huang, a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, "Our findings suggest that a big fraction of Warm Jupiters cannot have migrated to their current positions dynamically and that it would be a good idea to consider more seriously that they formed where we find them."

Warm Jupiters are large, gas-giant —planets found around stars other than the Sun. They are comparable in size to the gas-giants in our Solar System. But unlike the Sun's family of giant planets, Warm Jupiters orbit their parent stars at roughly the same distance that Mercury, Venus and the Earth circle the Sun. They take 10 to two hundred days to complete a single orbit.

Artist’s rendition of Kepler spacecraft. Credit: NASA/Kepler mission/Wendy Stenzel

Because of their proximity to their parent stars, they are warmer than our system's cold gas giants—though not as hot as Hot Jupiters, which are typically closer to their parent stars than Mercury.

It has generally been thought that Warm Jupiters didn't form where we find them today; they are too close to their parent stars to have accumulated large, gas-giant-like atmospheres. So, it appeared likely that they formed in the outer reaches of their planetary systems and migrated inward to their current positions, and might in fact continue their inward journey to become Hot Jupiters. On such a migration, the gravity of any Warm Jupiter would have disturbed neighbouring or companion planets, ejecting them from the system.

But, instead of finding "lonely", companion-less Warm Jupiters, the team found that 11 of the 27 targets they studied have companions ranging in size from Earth-like to Neptune-like.

"And when we take into account that there is more analysis to come," says Huang, "the number of Warm Jupiters with smaller neighbours may be even higher. We may find that more than half have companions."

Explore further: Some giant planets in other systems most likely to be alone

More information: Chelsea Huang et al, WARM JUPITERS ARE LESS LONELY THAN HOT JUPITERS: CLOSE NEIGHBORS, The Astrophysical Journal (2016). DOI: 10.3847/0004-637X/825/2/98

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wduckss
2 / 5 (4) Jul 14, 2016
Welcome attempt to change the paradigm.
Only the body in close orbitals have the option - slow distancing due to faster growth and approaching in the absence of growth (distortion of of harmony of orbit).
torbjorn_b_g_larsson
4 / 5 (8) Jul 15, 2016
It is interesting considering the recent observation that ice lines can move a factor 10 in a few years, so their distances are more what you'd call "guidelines" than actual rules.

But the paper didn't survey the possibilities for migration with the observed result, they just found the hypothesis a likely one.

@wdckss: There is no "paradigm" to change, just a consensus theory that is to be tested with observations such as presented here.

I don't understand the last half of your comment. (What is "the option" and what is "harmony of orbit" in relation to planetary system formation science?)
Mark Thomas
3 / 5 (6) Jul 16, 2016
Add this to the long and growing list of reasons why the galaxy is likely to be incredibly interesting, diverse, dynamic and unpredictable. This amazing universe is calling us to come out and play. We can start by getting out of low Earth orbit (LEO), something no person has done since 1972.
Nik_2213
4.2 / 5 (5) Jul 17, 2016
"We can start by getting out of low Earth orbit (LEO), "

Sadly, true, Mark. We trashed the jigs so couldn't make more of the 'long canoes' that crossed the narrow strait to our nearest island, have been faffin' about with coracles and coastal crannogs ever since.

Of course, there's still the non-trivial hazard of losing deep-space astronauts to solar flares. IIRC, there was one between Apollo missions that would have lethally zapped an en-route crew...
jonesdave
2.6 / 5 (5) Jul 17, 2016
Welcome attempt to change the paradigm.
Only the body in close orbitals have the option - slow distancing due to faster growth and approaching in the absence of growth (distortion of of harmony of orbit).


Dafuq is this?
Mark Thomas
2.6 / 5 (5) Jul 18, 2016
Nik_2213, I agree, in fact radiation is probably the #1 concern right now, but nobody said it would be easy. NASA keeps a copy of what President Kennedy said in his speech at Rice University in 1962 (http://er.jsc.nas...lk.htm). He mentions the dangers more than once, but I believe his conclusion said it best:

"Many years ago the great British explorer George Mallory, who was to die on Mount Everest, was asked why did he want to climb it. He said, 'Because it is there.' "

"Well, space is there, and we're going to climb it, and the moon and the planets are there, and new hopes for knowledge and peace are there. And, therefore, as we set sail we ask God's blessing on the most hazardous and dangerous and greatest adventure on which man has ever embarked."
Mark Thomas
2.6 / 5 (5) Jul 18, 2016
Space exploration is nothing less than "the most hazardous and dangerous and greatest adventure on which man has ever embarked."

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